Cordylite-(Ce) mineral

A natural barium-rare-earth fluorocarbonate mineral with the IMA-CNMNC September 2026 formula (Na,Ca,□)BaCe2(CO3)4(F,O), where □ denotes a vacancy. The authority lists renamed status and 1987 special procedure; this is not an IMA approval accession. This record denotes the Ce species, distinct from cordylite-(La), a rare-earth commodity or a mixed ore. Giester et al. (1998) investigated six specimens by chemical analysis and single-crystal X-ray diffraction and a seventh by X-ray methods alone, from Narssarssuk in Greenland, Mont Saint-Hilaire in Canada, Bayan Obo in China and the Kola Peninsula in Russia. The seventh crystal, original Flink material M.M. no. 392 (Narssarssuk 1*), suffered beam damage that prevented standard microprobe analysis; its qualitative EDX signal establishes Na presence without a quantitative Na concentration. The seven structures were refined in P63/mmc. Attempts in the lower-symmetry alternative P-62c did not give conclusive grounds to prefer it. The paper's idealized formula (Na1-xCax/2)BaCe2(CO3)4F, with 0 <= x <= 1, uses Ce as a proxy for the sum of rare-earth elements, not a measured pure-Ce endmember. X-ray scattering alone cannot resolve the Na/Ca proportion; the separate chemical analyses constrain it. CO2 in Table 5 is calculated by difference, selected Na determinations used direct-current argon-plasma spectrometry, and reliable water analysis was unavailable. These distinctions preclude treating all reported contents as direct microprobe measurements. Comparative and type material support the authors' identification of historical baiyuneboite-(Ce) as cordylite-(Ce) and revision of the older formula; the broader current IMA formula is retained separately from their 1998 model. Printed atomic coordinates and distances were inspected, but deposited anisotropic displacement Table 3 (AM-98-005) was not acquired. No controlled extraction, microbial mechanism, recovery yield, industrial deployment or transferred criticality designation is asserted.

Record source: data/records/cordylite-ce.yaml